Messages in this thread | | | Date | Mon, 9 Jul 2018 14:19:19 -0400 (EDT) | From | Mathieu Desnoyers <> | Subject | Re: [PATCH for 4.18 2/6] rseq: use get_user/put_user rather than __get_user/__put_user |
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----- On Jul 9, 2018, at 2:04 PM, Linus Torvalds torvalds@linux-foundation.org wrote:
> On Mon, Jul 9, 2018 at 10:28 AM Mathieu Desnoyers > <mathieu.desnoyers@efficios.com> wrote: >> >> So, another twist to this story: ppc32 does not implement u64 get_user(). > > I was going to say that "that's not possible", since we actually have > 64-bit arguments at least in the form of "loff_t __user *". > > But when I started looking, it turns out that yeah, we do > "copy_from_user()" on them, and instead made the x86 copy_from_user() > have special cases for constant sizes. > > So a 8-byte copy_from_user() is fine. It ends up being a "get_user()" > on x86 anyway.
Given that this memory area has already been checked with access_ok() on rseq registration, are you fine with leaving __get_user/__put_user/__copy_{from,to}_user in place so we do the minimal change at this stage of rc, or should I go ahead and replace the lot with get_user/put_user/copy_{from,to}_user ?
Thanks,
Mathieu
-- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com
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